There are many metrics defined on trees, which can be roughly classified into three groups by their ideas: (1) Calculate the minimal operations needed to transform one tree into another, such as rearrangement distance [1]}, tree edit distance [2]}, edge rotation distance [3]}, and geodesic distance [4]}. (2) Find the largest common structure of two trees, such as bottom-up distance [5]} and subtree distance [6]}. (3) Compare structures induced by the trees (e.g., splits or triple-vertices subtrees), such as Robinson-Foulds metric [7]}, matching cluster distance [8]}, and triples distance [9]}.
